Publisher's Synopsis
Ever wish you were better at mental arithmetic? Young or old, everyone can sharpen their mental math skills and rejuvenate the grey matter with these incredibly simple but effective puzzles straight from the desk of the original and best 30 Second Challenge math master. See how quickly you can work your way through each puzzlefrom beginner to advanced leveland feel your mental agility improve every day. Compelling, fun, and suitable for all ages and abilities, this is the ultimate brain-training tool for people on the go.
